Convert HTTP requests to SOCKS5

It looks like DeleGate can do this, with something like the following (where DeleGate will accept HTTP connections on port 8080 and forward to a SOCKS server on port 9050):

delegated -P8080 SERVER=http SOCKS=localhost:9050

You can also use Privoxy. Add this line to its config.txt file:

forward-socks5 / 127.0.0.1:9050 .

(Don't forget the small dot at the end.)

Then use the HTTP or HTTPS proxy at 127.0.0.1:8118

Tor bundle no longer has polipo, here is from the official tor FAQ:

In the past, Tor bundles included an HTTP proxy like Privoxy or Polipo, solely to work around a bug in Firefox that was finally fixed in Firefox 6. Now you don't need a separate HTTP proxy to use Tor, and in fact leaving it out makes you safer because Torbutton has better control over Firefox's interaction with websites.

If you are trying to use some external application with Tor, step zero should be to reread the set of warnings for ways you can screw up. Step one should be to try to use a Socks proxy rather than an http proxy — Tor runs a Socks proxy on port 9050 on Windows, or see above for OSX and Linux.

If that fails, feel free to install privoxy. However, please realize that this approach is not recommended for novice users. Privoxy has an example configuration of Tor and Privoxy.